Switching device with cams pivotal about an axis parallel to the plane of movement of switch plungers

ABSTRACT

A mechanism to operate a plurality of pairs of plunger actuable switch contacts in sequence wherein the plungers are pins axially slidable for switch actuation. A plurality of shafts are threaded through a pivoted lever. Each shaft carries a frusto-conical cam to engage one end of a corresponding pin. All the pin, shaft and cam axes are parallel, the lever being movable on a frame in a direction perpendicular to the said axes. Threaded engagement of the shafts with the lever makes possible individual adjustment for calibration. It is thus possible to determine when each switch is actuated without complete disassembly.

United States Patent Tabares et al.

SWITCHING DEVICE WITH CAMS PIVOTAL ABOUT AN AXIS PARALLEL TO THE PLANE OF MOVEMENT OF SWITCH PLUNGERS lnventors: Gilbert Tabares, Panorama City; Joseph Clifford, Corona, both of Calif.

International Telephone and Telegraph Corporation, New York, NY.

Filed: July 16, 1970 Appl. No.: 55,451

Assignee:

References Cited UNITED STATES PATENTS 2/1969 Haydon et al. ..200/153 L X 10/1969 Ziegler, Jr ..200/153 LA X 2/1971 Vollum et al. ..200/153 LB 6/1971 Ziegler, Jr. ..200/ 153 LA [151 3,655,932 [4 1 Apr. 11, 1972 Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney-C. Cornell Remsen, Jr., Walter J. Baum, Paul W. Hemminger, Thomas E. Kristofferson and Charles L. Johnson, Jr.

[ 57] ABSTRACT A mechanism to operate a plurality of pairs of plunger actuable switch contacts in sequence wherein the plungers are pins axially slidable for switch actuation. A plurality of shafts are threaded through a pivoted lever. Each shaft carries a frustoconical cam to engage one end of a corresponding pin. All the pin, shaft and cam axes are parallel, the lever being movable on a frame in a direction perpendicular to the said axes. Threaded engagement of the shafts with the lever makes possible individual adjustment for calibration. It is thus possible to determine when each switch is actuated without complete disassembly.

3 Claims, 5 Drawing Figures Patented April 11, 1972 2 Sheets-S; et l 6/L56Z TAB/466:5 FIG- 2 JOSG H CC/FFOKD I INVEN ORS' Patented April 11, 1972 3,655,932

2 Sheets-Sheet 2 ZE -q}. i :2 2.9

67 5627 74 5, 5 J056PH cal-"F060 SWITCHING DEVICE WITH CAMS PIVOTAL ABOUT AN AXIS PARALLEL TO THE PLANE OF MOVEMENT OF SWITCH PLUNGERS BACKGROUND, OF THE INVENTION This invention relates to switches and, more particularly, to time delay relays.

In the past, it has been the practice to locate a plurality of switches adjacent a moving member for switch actuation with a thermally expansible rod heated, on demand, by an electric heater winding. Prior art devices such as this require that each individual switch be adjusted to determine proper switching times. The adjustment of each switch, thus, makes it necessary to disassemble each switch individually and the entire assembly as well. A time-consuming calibration procedure is thus necessary simply in replacing one defective switch.

SUMMARY OF THE INVENTION In accordance with the device of the present invention, the above-described and other disadvantages of the prior art are overcome by providing a cam for each switch adjustable on a movable body. The body may be moved, for example, by the expansion rod.

With the device of the invention, the switch actuating posi tion of each cam may thus be individually adjusted easily and quickly. The time-consuming calibration procedures of the prior art are, therefore, avoided. The replacement of a single switch may or may not require calibration. If it does, calibra' tion may be easily performed by the adjustment of one or more of the cams.

The above-described and other advantages of the invention will be better understood from the following description when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is a top plan view of a switching device constructed in accordance with the present invention;

FIG. 2 is an end elevational view thereof;

FIG. 3 is an exploded perspective view of a cam-carrying member;

FIG. 4 is a sectional view through the pivot pin for the said member; and

FIG. 5 is a broken away view illustrating the operation of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, in FIG. 1, a switching device is indicated at including a frame 11. As shown in FIG. 2, frame 11 has rectangular side members 12 and 13 to which are fixed a crossbar 14.

As shown in FIG. I, a yoke 15 is fixed to the other ends of member 12 and 13.

A bracket 16 is also fixed to members 12 and 13. Bracket 16 has slots 17 in which screws 18 are located. Screws 18 are threaded into a body 19 of conventional switches or microswitches which have contact terminals or screws at 20.

Screws 19 also have contact terminals or screws 21 threaded into the switches 19 through holes, not shown, in a bus bar 22. Bus bar 22 need not necessarily be provided to practice the present invention, although it may be used, if

' desired.

As shown in FIG. 2, each switch 19 has an operating plunger 23 which is engaged by a corresponding carn threaded through an L-shaped member 25. More particularly, as shown in FIG. 1, L-shaped member 25 has a leg 26 and a leg 27. It is through leg 27 that carns 24 are threaded. Cams 24 have heads 28 and shanks 29. Shanks 29 have hex-end portions 30 so that cams 24 may be rotated to adjust their height relative to L-shaped member 25. As shown in FIG. 2, leg 27 is slidable on crossbar 14 although crossbar 14 is not absolutely needed to guide member 25. Note will be taken that from FIG. 4, L-shaped member 25 has a clevis 31 which is held firmly in place by a clevis 32 offrame 11 by a pin 33. As shown in FIG. 3, a leg 27 has a depending tab 34 which engages crossbar 14. A spring 35 shown in FIG. 1 is maintained in compression between a block 36 and leg 26 of member 25. Block 36 is welded to a bottom panel of frame 11 which terminates at 43. Panel 43 may be integral with a major portion of the length of each of the side members 12 and 13 of frame 11. Rotation of member 25 about the axis of pin 33 shown in FIG. 1 to the left is, thus, urged by spring 35, movement of member 25 about the axis of pin 33 to the left being limited by engagement of tab 34 with crossbar l4. Rotation of member 25 to the right is produced by a thermally expansive rod 37 located between an accompanying recess 38 in member leg 26 and accommodating recess 39 in the end of set screw 40. Rod 37 is heated by a resistive winding 41 when it is desired that switches 19 be actuated. Screw 40 has a screwdriver slot at the end thereof for adjustment of the cool position of rod 37.

As shown in FIG. 3, each cam has a fiat portion 44 and a frusto-conical portion 45.

In the operation of the switching device of the present invention, winding 41 is heated and rod 37 elongates. L-shaped member 25 is then rotated to the right about the axis of pin 33. Cams 28 then in succession actuate one or more switches at a time. The device 10 is, thus, a sequence switching device. Note will be taken that the use of a small taper of the conical surface 45 makes it possible to have a wide variation or adjustment of each cam 44 by rotation thereof into the threaded connection thereof through leg 27 of L-shaped member 25. Moreover, the leftmost cam 24 will move at a rate greater than any of the other cams. Each successive cam to the right will rotate at a lower speed. This is due to the fact that each cam is located at a successively smaller radius than the previous cam.

In FIG. 1, movement of member 25 from its dotted line position is indicated at 25.

What is claimed is:

1. A device for closing a pair of electric switch contacts, said device comprising: a movable rigid body; at least a first switch fixed in position adjacent said body said switch having an operating plunger; at least a first cam for said switch mounted on said body; and means to move said body in a direction such that a point on the cam describes a line in a plane perpendicular to the plunger axis, said cam moving said plunger during movement of said body, said cam having a tapered surface to move said plunger, said body being an L- shaped member pivoted near one end, said device including a plurality of cams mounted at different positions along the length of the leg of the L at the other end thereof, said body being pivoted by a thermally responsive rod engaging said one end beyond the pivot, said rod being held in compression between said body and another support, said support including a fixed frame having a threaded hole therethrough and a set screw threaded through said hole, said other leg of said body having a threaded hole therethrough for each cam, each cam including a generally frusto-conical head to engage a switch plunger and a shank threaded in a corresponding hole in said other leg, said shanks each having a hex head at the ends thereof for rotation of said cams about the axis of said shank, said cam rotation producing movement of said heads in the direction of said shank axes relative to said body, each frusto-conical head surface being symmetrical about a corresponding shank axis, said device including a spring to bias said body against said rod, sa'id frusto-conical surfaces terminating in flat surfaces perpendicular to said shank axes.

2. A sequence switching device comprising: a frame; a rigid body movably mounted on said frame; at least first and second switches fixed relative to said frame, said first and second switches having first and second plungers, respectively, movable in a predetermined direction for switch actuation, at least first and second cams for said first and second switches, respectively; both of said cams being mounted on said body; and means to move said body in a direction perpendicular to plungers, said body being pivoted about an axis parallel to those of said plungers.

3. The invention as defined in claim 2, wherein said frustrums are terminated at the smaller diameter ends thereof with a flat circular surface lying in a plane perpendicular to the axes of said plungers. 

1. A device for closing a pair of electric switch contacts, said device comprising: a movable rigid body; at least a first switch fixed in position adjacent said body said switch having an operating plunger; at least a first cam for said switch mounted on said body; and means to move said body in a direction such that a point on the cam describes a line in a plane perpendicular to the plunger axis, said cam moving said plunger during movement of said body, said cam having a tapered surface to move said plunger, said body being an L-shaped member pivoted near one end, said device including a plurality of cams mounted at different positions along the length of the leg of the L at the other end thereof, said body being pivoted by a thermally responsive rod engaging said one end beyonD the pivot, said rod being held in compression between said body and another support, said support including a fixed frame having a threaded hole therethrough and a set screw threaded through said hole, said other leg of said body having a threaded hole therethrough for each cam, each cam including a generally frusto-conical head to engage a switch plunger and a shank threaded in a corresponding hole in said other leg, said shanks each having a hex head at the ends thereof for rotation of said cams about the axis of said shank, said cam rotation producing movement of said heads in the direction of said shank axes relative to said body, each frusto-conical head surface being symmetrical about a corresponding shank axis, said device including a spring to bias said body against said rod, said frusto-conical surfaces terminating in flat surfaces perpendicular to said shank axes.
 2. A sequence switching device comprising: a frame; a rigid body movably mounted on said frame; at least first and second switches fixed relative to said frame, said first and second switches having first and second plungers, respectively, movable in a predetermined direction for switch actuation, at least first and second cams for said first and second switches, respectively; both of said cams being mounted on said body; and means to move said body in a direction perpendicular to said predetermined direction, said cams moving their corresponding plungers during movement of said body, each cam having a tapered surface to move each corresponding plunger, said cams having shafts adjustably threaded through corresponding spaced holes in said body, said holes having parallel axes, both of said plungers being located on the same side of said body, said cam surfaces being frustrums of cones with the smaller diameters thereof being located the closest to said plungers, said body being pivoted about an axis parallel to those of said plungers.
 3. The invention as defined in claim 2, wherein said frustrums are terminated at the smaller diameter ends thereof with a flat circular surface lying in a plane perpendicular to the axes of said plungers. 